Call transmitter



y 1, 1945 J. OD. SHEPHERD cALL TRANSMITTER Filed Dec. 19, 1940 2 Sheets-Sheet 1 AT TORNEV May 1945- J. on. SHEPHERD CALL TRANSMITTER 2 Sheets-Sheei 2 Filed Dec. 19, 1940' IN VEN TOR BVJ. 0'0. SHEPHERD ATTORNEY Patented May 1, 1945 CALL- TRANSMITTER Judson OD. Shepherd, Atlanta, Ga.

2 Claims.

This invention relates to telephone call transmitters and more specifically to call transmitters of the finger wheel operated type.

In call transmitters now in use, a finger wheel is provided with ten finger holes disposed in registry with digits, or groups of letters and digits, in combinations printed on the face of a number plate, one group comprising a cipher and the word operator, the word operator representing ten impulses used for calling the operator at the central office district.

In certain localities a telephone service is rendered which requires that all calls, or those from particular telephones, must be routed at the automatic central oifice through an operator by the signaling of the word operator in the ordinary manner. In call transmitters now in use it has been found that subscribers are liable to initiate any desired call without being routed at the automatic central oiiice to the operator -lfor the reason that in these call transmitters the impulse mechanism is always responsive to any selective operation of the finger wheel.

The object of the invention is to provide a telephone call transmitter which will be simple, efiicient in use and in which the movement of the finger wheel is rendered effective only in the signaling of those digits which, individually, involve the transmission of more than a predetermined minimum number of pulses.

In the drawings,

Figure 1 is a plan view showing the finger wheel in normal position.

Fig. 2 is aside view showing a number of operatin parts in vertical section taken on lin 2-2 of Fig. 1.

Fig. 3 is a top view shown with the finger wheel removed from its supporting shaft and a number of operating parts with portions cut away, the driving clutch element carried by the finger wheel being shown disengaged from its driven associated clutch element;

Fig. 4 is a view similar to that of Fig. 3 shown with the driving and driven clutch elements in engaged relation following the movement of the finger wheel from normal to operated position as limited by the finger stop;

Fig. 5 is a partial view showing the drivin clutch element carried by the finger wheel held disengaged from its associated. clutch element following a small angular movement of the finger wheel toward its operated position;

Fig. 6 is a partial view shown in vertical section taken on line 6-6 of Fig. 5;

Fig. 7 is a partial view in vertical section taken Application December 19, 1940, Serial No. 370,761

on line 1-1 of Fig. 3 showing the pawl which limits the direction of the pulsing cam to one direction in engaged relations with this cam;

Fig. 8 is a plan view shown with a number of operating parts with portions cut away to show the retaining pawl and the pulsing pawl in engaged relation with the pulsingcam;

Fig. 9 is a partial view of the call transmitter showing a modification of the clutch pawl actuating mechanism, the pawl being shown disengaged from its operatively associated clutch wheel; and

Fig. 10 is another partial View showing the clutch pawl in ngaged relation with the clutch wheel.

The call transmitter of this invention may consist, for example, of a Casing ii) having a centrally disposed bearing H, best seen in Figs. 2, 6 and 7, in which a shaft i2 is rotatably mounted, and on the periphery of bearing H is mounted for rotary movement thereon, as a unit, the gears i3 and. l3A provided for a p pose which will be hereinafter described in detail. Bearing H is provided with a reduced portion for rotatably mounting, as a unit thereon, in superposed relation to gears i3 and I3-A a pulsing cam 14 and a clutch element in the form of a notched wheel it. To the upper end of shaft 12 is keyed a finger wheel 48 having a finger hole H through which the call designation Operator for example, may be visually observed, such designation being printed on a number plate NP supported by a ring 25 formed with three supporting arms 26, 21 and 28 secured to the casing iii by a number of screws 29, the supportin rin havin a stop arm il cooperating with the head of a screw it! carried by the finger wheel it for holding this finger wheel in its normal position against the normal tension of a motor spring ll.

To the lower end of shaft 12 is keyed a gear IE to which one end of motor sprin ii is secured while the other end of this spring is hooked to the casing it) as shown in Fig. 2, so that the rotation of finger wheel [8 from normal position shown in Fig. 1 to the fully operated position as limited by a finger stop 3'! as indicated indotted line in Fig. 4 is eflective to tension the motor spring ll, the function of which is to re: turn the finger wheel to normal position while actuating the pulsing cam M in a manner which will be hereinafter described in detail.

The gear l6 meshes with a pinion it provided for imparting movement to a pinion 20 through ating the weightsWzand W1 of a centrifugal .gov-

ernor serving for controlling the operation of the pulsing cam I4 during the return movement of the finger wheel I8 under the tension of motor spring II, the movement of the finger wheel .heing imparted to the cam I4 through a driving clutch element in the form of a spring-pressed clutch pawl 22 pivoted to the underside;uf fin ger wheel I8 on the screw 48:, and thenotched wheel I5, the engagement and disengagement of these clutch elements being effected according to .the.direction ormovement of the finger wheel by the cooperation of a cam 30 and aband or split rim ,3 Y formed with a ring 23 itself secured to the supporting ring 25, v

A double-armed lever or pawl 3| which is pivoted on a spindle 32; journaled in brackets 33 and 34 of casing III is provided with a retractilespring SP shown in Fig. 2, for yieldably holding one arm of this pawl in operative relation with the pulsing cam is, while its other arm extends in engageable relation with an operable pulsing spring 35 for operating it upon the rotation of cam .I a. The spring 3,5 together with its associated contact spring 35-A is mounted in a pile-uparrangement-on a bracket 34 shown in .Fig. 2 and provided with terminals TI and T2 to which are attached conductors CI and C2 of an external circult to be pulsed.

The finger stop 3,! is secured to the rim portion of casing II! by screws 38, to serve for limiting the angular movement of the finger wheel l8 ,from its normal position shown in Figs. .1, .2 and 3 .to its-operated position shown in dotted line inFig. 4.

o the u d s de-oi supporting rin .2 5 as shown in Figs. 2, 3, Hand 3 1s mounted a pawl 4,5 held in engaged relation with the pulsing cam I4 by a sprin SPI 3. .01. limiting the .movement of this cam toone direction for a'purpose which will be hereinafter described in detail.

In a typical example of operation of the call transmitter of this inventiomthe angular movement of finger wheel I8 and the clutch pawl 22 carried thereby from normal position, best seen in Figs. 1,8 and 8, to its operated position as determined :by the finger stop 3i, as shown in dottedjlinein Fig. 4, is effective to tension the motor spring i1 and'causes the clutch pawl 22 due to the shape of cam 39 to move first onto the periphery of clutch wheel I5, as at point P2, shown in Fig. 3, from which point this pawl is cammed onto the periphery of rim 3IIY formed with ring 23 against the tension of its retractile springX' as efiected by the camming end of that ring, thus rendering the movement of the finger wheel ineffective relative to clutch wheel I5 to a point CD of that rim where the clutch pawl 221s caused to engage, for example, the notch Bl under the tension of its retractile spring X. The movement of finger wheel I8 in its clockwise direction, i. e.,, from normal position to operated position is effective to rotate the gear I3 and thereby the pinion IS in a direction inefiiective relative ,to clutch spring 2i, so that pinion za'tnegears .I3-.Aand I3 .andthe unit rormed of pinion 38B and gear 3llD, and the speed governor connected to the latter gear are not actuated,

Upon the release of the finger wheel l8 by the operator, this wheel is returned to normal position under the tension of motor spring II, thus rotating the clutch wheel I5 and the pulsing cam I4 carried thereby due to the engagement of pawl 22 with wheel I5, the rotation of pulsing cam L4 being effective to actuate the double armed lev'er EI .and thereby the pulsing spring 35 ten times, the number of pulses corresponding to the number of teeth of cam I4, i. e., the call designation Ope'rator The speed of rotationof this cam is controlled by "the centrifugal governor having its driving pinion ,3fi-E actuated from gear it through pinion I9, the clutch spring 2! now effective to operate the-pinion 20, engaging the-gear I3-A-movable as a unit with gear 13 and in mesh with pinion 39-13 rotating as a unit with gear 3IID in turn engaging the pinion39-E of the speed governor.

Upon the engagement of clutchpawl 22 carried by the finger wheel I 8 with the cam portion 30 which occurs a small angular distance from the normal position of the finger wheel, the pawl 22 is cammed out of engagement from'notch BI of clutch wheel -I'5,'while the finger wheel continues its movement as limited by the stop aiforded by the head of screw 40 carried by the finger wheel in the path or the upwardly extending lug 'i formed with 'the'supporting plate 25 as shown in Fig. 2, and this cycle of operation is repeated for each call Operator 0 transmitted.

The pawl 4'5, Fig. .3, pivoted on supporting ring 25 and spring pressed against the impulse wheel I4, is provided to prevent subscribers from callingany otherdigitthan the one authorized. This pawl accomplishes this function by preventing a subscriber from allowing Ithe finger Wheel to be returned part Way back to normal under the tension of the motor spring and then interrupting itsmovement and rotating it back to the finger stop and releasing it again in an attempt to-dial call designations other than Operator which are not routed to the operator at the automatic central office, for example.

In the modification shown in Figs. 9 and 10, the supporting plate 25 is provided with an upwardly extending cam 50 which cooperates with the cam 38, also formed with this supporting plate, for imparting pivotal movement to the clutch pawl 22 for engaging it and disengaging it from the clutch wheel l5 depending upon the direction of rotation of the finger wheel 18, the pawl 22 being yieldably held in each position by a spring 5i hooked to the pawl 2.2 by a pin 52 and to the finger wheel is by ,a pin 53,, in the manner of a toggle mechanism,

In an example of operation of this modification and considering the pawl .22 in position shown in Fig. 9, themoyementof the finger wheel I8 to its operated position as determined *by the finger stop 31 is effective to ,move the pawl22 to a point where the pin Ii-carried thereby engages the cam 15.9 whichcauses .a pivotal movement to the pawl 22 until the longitudinal axis of spring passes the center of pivot screw 40 to cause the automatic continued movement of this pawl under the tension of spring 5| to a point where the pin Y carried by this pawl engages one of the notches b as the case may be.

The release of finger wheel I8 and its consequent return movement to normal position is eifective to rotate the clutch wheel l5 and the pulsing cam l4 for actuating the pulsing pawl 3| in the manner above described in connection with the call transmitter shown in Fig. 1. Upon the engagement of pin Y of pawl 22 with cam 30 this pawl is pivoted to a point where the spring 5! again passes on the other side of the center of pivot screw 40 to hold this pawl in the position shown in Fig. 9 and the transmitter is now ready for a subsequent operation,

It is to be noted that the uncontrolled return movement of the finger wheel IB is prevented by the operation of the governor mechanism from any angular position the finger wheel may have been moved from normal position and this independently of the operation of the pulsing cam.

While the invention has been shown and described in certain particular embodiments, it will be understood that it may be embodied in other organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. In a call transmitter, a shaft rotatable in two directions, a finger wheel and a gear keyed to said shaft for movement in both of said directions, acasing, a hub element secured to and projecting from said'casing and serving as a bearing for said shaft, a motor spring having one end hooked to said casing and its other end to said gear to be tensioned by the movement of said gear in one of said directions, a notched Wheelpulsing cam unit mounted for free rotation on said hub element, a pawl mounted on said finger wheel associated with the notched wheel of said unit, a retractile spring therefor, a stationary ring secured to said mounting and having a ridge, a cam carried by said ring cooperating with means formed with said ridge for controlling the operation of said pawl in one direction of rotation of said finger wheel for guiding said pawl onto the outer periphery of said ridge, and at the termination of said movement guiding it inwardly of said ridge into engagement with a notch in said wheel under the tension of said retractile spring, said finger wheel being restored to normal by said motor spring upon its release and. due to said pawl engaging said notch, driving said notched wheel-pulsing cam unit, a pair of gears mounted for free rotation as a unit on said hub element, a pinion engaging one of said gears in said gear unit, a pinion engaging the gear keyed to the shaft, a one-way friction clutch operatively connecting the first and second mentioned pinions for rotating said gear unit upon the movement of said finger wheel as imparted by the tension of said motor spring, and a governor mechanism actuated by the other of the pair of gears in said gear unit for governing the speed of said pulsing cam.

2. In a call transmitter, a casing, a hub element carried by 'said casing and extending perpendicularly on both sides thereof, a shaft mounted for free rotation in said hub element, a pair of gears secured to each other as a unit and mounted for free rotation on said hub element, a notched Wheel-pulsing cam unit mounted for free rotation on said hub element in superposed relation to said gear unit, a finger wheel keyed on one end of said shaft, a motor spring tensioned by the movement of said finger wheel in one direction for moving said shaft in the other direction, a gear keyed on the other end of said shaft, a inion engaging one of said gears in said gear unit, a pinion engaging the gear keyed .on said shaft, a one-way friction clutch element operatively connecting the first and second-mentioned pinions, a pinion engaging the other gear of said gear unit, a gear movable as a unit with the lastmentioned pinion, a governor mechanism actuated by the last-mentioned gear under the tension of said motor spring for controlling the operation of said notched wheel-pulsing cam unit, a stationary ring disposed concentric to said pulsing cam having a circular ridge and a camming element, a pawl carried by said finger Wheel having a retractile spring, said spring cooperating with said ridge and said camming element for causing said pawl to engage a notch in said wheel on the termination of the setting movement of said finger wheel, and a pulsing mechanism actuated by said pulsing cam unit during the restoration to normal of said finger wheel under the influence of said motor spring.

JU'DSON OD. SHEPHERD. 

